As the
population of Bangladesh increases, so do the processes of industrialisation and
urbanisation. The number of vehicles is also increasing. Manufacturing plants
are multiplying to meet the growing needs of the population. The result is an
increased threat of noise induced hearing loss, annoyance and other adverse
effects on the health and well being of the population.

According to
dependence on time, noise may be classified as steady, non-steady, fluctuating,
intermittent impulsive, quasi-steady, ambient, etc. steady noise is a noise with
negligible small fluctuations of level within the period of observation.
Non-steady noise is a noise whose level shifts significantly during the period
of observation. Fluctuating noise is a noise whose level varies continuously and
to an appreciable extent during the period of observation. Intermittent noise is
a noise whose level suddenly drops to the level of the background noise several
times during the period of observation, the time during the level remains at a
constant value. Impulsive noise is a noise consisting of one or more bursts of
sound energy.

A study was
recently in the cities of Dhaka, Chittagong and Khulna by DOE, sponsored by
World Health Organisation (WHO), to measure the extent of sound pollution, types
of noise, sources of noise and exposure of noise. It specifies sensitive
localities of the three cities of Bangladesh where public health is liable to be
affected by noise pollution. Classification of the surveyed areas of the three
cities on the basis of the level of noise pollution, comparison of observed
noise level of the surveyed localities to the noise level permissible for those
areas by the government of Bangladesh leading to identification of severe,
moderate, mild red zone areas and green zone areas have been mentioned in the
survey reports.

Out of 45 areas
surveyed in Dhaka city, 29 showed noise level above the permissible limits
accepted by DOE. According to the severity of the noise pollution they are
sub-classified as severe red zone, a moderate red zone and mild- zone areas. The
remaining 16 areas showed noise level fluctuating in and around the permissible
limits accepted by DOE.

The highest dB
of 100 in Dhaka city was observed at Zia International Airport take off point of
plane in contrast to permissible limit of 85 dB. The lowest 50 dB was observed
at National Institute of Preventive and Social Medicine (NIPSOM) though the
permissible limit was 45 dB. The green zone areas are also vulnerable to
increasing to noise pollution beyond the permissible limits in decibel due to
many factors, such as increased population, increase number of vehicles,
unregulated miking, clamor from construction works and factories, etc.

The level of
noise pollution in 10 representative areas in Dhaka city has been specified as
follows:

Areas

Type of
Area

Observed
dB

Permissible
limit

level
of noise pollution

Shakhary
Patty

Residential
Area

75.5 dB

45 dB

25.5

Shaheen
School

Silent
Zone

67.8 dB

45 dB

22.6

DMCH­

Silent
Zone

70.8 dB

45 dB

25.8

Inside
NBF­­

Industrial
Area

89.0 dB

75 dB

14

Mohakhali
Bus Terminal

Busy
Traffic

89 dB

85 dB

04

New
market

Commercial
Area

86.4 dB

70 dB

16.4

Mouchak

Mixed
Area

92.6 dB

60 dB

30.6

Motijheel
C/A

Commercial
Area

82 dB

70 dB

12

Banani
R/A

Residential
Area

61 dB

50 dB

11.4

Bashabo
Temple

Silent
Zone

65.25
dB

45 dB

20.25

­
Dhaka Medical College Hospital

­­
Nabisco Buiscuit Factory

The
findings indicate that noise pollution exists in Dhaka city in an epidemic
form.

Noise
pollution in Chittagong city

Forty-five
locations covering silent, residential, commercial industrial and mixed areas in
Chittagong city were surveyed to determine the noise level limit. Out of 45
areas, 28 showed noise level exceeding permissible limits and 17 showed noise
level fluctuating in and around the permissible noise level. In other words, 62
per cent of the surveyed areas in Chittagong city showed noise level higher than
the acceptable limits. The noise level of 36 areas of Chittagong city showed a
similar pattern of level compared to that of 36 areas of Dhaka.

Noise
pollution in Khulna city

Thirty-four
areas in the Khulna city were surveyed, of which 18 showed noise level exceeding
the permissible limit. The highest observed decibel in Khulna city was found to
be 95.6 decibel in Shiromoni BSCIC Industrial Area, where the permissible noise
limit is 75.6 decibel. The lowest noise 58.60 decibel was observed in Khalishpur
Residential Area where the permissible limit is 50 decibel . The finding
establishes the existence of noise pollution in an epidemic form in Khulna city.

The findings of
the survey on noise pollution in the city of Dhaka, Chittagong and Khulna not
only establish the existence of the grave situation of noise pollution in the
three cities but also bear testimony to the perdition of ENT specialists of the
country, which read as follows:

After 20-25
years, 50 of percale of the population of Dhaka city would be losing their
hearing capacity by 30 dB, of immediate steps are not taken to prevent, control
and monitor noise hazard ill effects and annoyance produced by noise pollution.

To face the
epidemic situation of noise pollution it is necessary to raise people’s
awareness to curb noise pollution by focussing or reducing the use of
noise in traffic.

·
Implementation of regulations prohibiting use of hydraulic horns, as well as
stopping import, and marketing of hydraulic horns.